(a) Field of the Invention
The present invention relates generally to electronic mail in a network environment and, more particularly, to a hybrid network system having a one-way, continuous, high-speed (e.g., at least one megabit per second) broadcast communication channel allowing a computer server to transmit packetized data such as electronic-mail status information to one or more computer terminals and also having a switched communication channel, which may operate at a relatively lower speed, for permitting a user of the terminal to interact with the computer server. The present invention uses such a hybrid network to transmit electronic mail status information from an electronic mail server to a terminal and to allow electronic mail to be retrieved from the electronic mail server via the terminal.
(b) Description of Related Art
The use of electronic mail or Ile-mail,, as a mode of communication has proliferated in the past several years, both in the local-area network (LAN) environment and in the environment of wider-area networks, such as the internet, for example. Clearly, one important facet of any e-mail system is that e-mail recipients must be notified that they have received e-mail messages so that they know to retrieve them, read them, and, if necessary, respond to them.
In an inter-LAN e-mail system (i.e., a system for distributing e-mail from one LAN user's terminal to another), notifying the e-mail recipient is relatively straightforward, because each LAN terminal, by its nature, is continuously connected to the local area network so that a notification can be sent to the LAN terminal (or an e-mail message can be retrieved by the LAN terminal) at any time. Accordingly, various systems have been provided for m handling e-mail notifications in the LAN environment. For example, an audible or visual notification can be provided at a LAN terminal or workstation being used by the e-mail recipient. If the e-mail recipient is not logged on to the LAN when the e-mail message is sent, the notification is typically stored in a buffer and is presented to the recipient when she next logs on. Because the LAN connection is continuous, only minimal overhead costs are incurred in providing a transmission path for e-mail notifications.
Notifying an e-mail recipient that she has received e-mail is more problematic, however, in a broader network, such as the internet, where the connection between the terminal or workstation used by the e-mail recipient and the physical network is often a switched connection, such as a dial-up modem connection or an ISDN connection, rather than a continuous connection. Conventionally, an e-mail service subscriber must periodically access the network via a dial-up or other switched connection and must enter a subscriber identifier and a password to be informed of awaiting e-mail messages and then to retrieve any such messages via the dialup connection. Prior to accessing the network in this manner, the subscriber does not know whether any e-mail has been sent to him, and could go through this dial-up process numerous times before actually receiving an e-mail message.
To simplify the task for e-mail subscribers, the dial-up process has been automated to some extent, such as by providing subscriber hardware for automatically dialing in to a network or e-mail server periodically; automatically entering the subscriber identifier and password; and automatically checking for e-mail messages for a subscriber; and possibly also for automatically downloading the e-mail messages for the subscriber.
Nonetheless, each of these prior-art systems requires repeated access to a telephonic or other switched connection to the network or e-mail server and requires active processing by the terminal or workstation of the e-mail subscriber before the notification is received by the subscriber. Moreover, connection to the network via telephone may require long-distance telephone calls which can be expensive for users. Further, such repeated telephone access requires excessive use of finite telephone network resources as well as users' valuable telephone lines and thus potentially prevents the users from receiving incoming telephone calls.
One prior-art solution has been to send e-mail notifications to e-mail subscribers via wireless pagers using a low-speed, unidirectional, terrestrial broadcast. The obvious shortcomings of this system are that a user must incur the cost and inconvenience of carrying a pager to receive notifications, and that the e-mail service must employ a terrestrial (e.g., cellular) communication facility to transmit e-mail notifications, which adds significantly to the overhead costs of the e-mail service. Moreover, the pager notifications are not integrated with the computer network, and notifications therefore cannot be transmitted directly to subscribers' computer terminals.
Some hybrid computer network systems have been developed, but those systems do not provide functionality for e-mail notification and e-mail message transmission. In that respect, previously developed hybrid computer network systems operate like conventional network systems, employing only low-speed, switched communication channels for on-request e-mail message retrieval.